I have been using PIR sensors for presence detection on Halloween props at my home for several years and got them working well with experimentation. I am interested to take a step up and look at gesture recognition, such as waving, but from a ‘normal waving distance’ of 2-10 ft, outside, in the dark. Most explicit gesture sensors work up to about a foot I think. This is a gigantic rabbit hole, because it seems almost any technology can detect ‘motion’, ir, ultrasonic, pir, radar, optical, machine vision, microwave, laser… I just want to be able to detect if a person is waving at the prop and disregard other non-waving motion. So with signal processing I thought I could detect repetitive or oscillating signal variation and use that within a certain frequency range to detect waving, 1D detection. Even using 2 ultrasonic sensors to detect back and forth motion might do it. Low cost is a constraining factor as I have ~10 props and a limited budget, so I was thinking ~ $10-20/ application. I am investigating openCV as a last resort. Does anyone have ideas as to what type of a low-cost system might work here?
I would be inclined to recommend using OpenCV and some esp32CAM boards